1) Field of the Invention
The present invention relates to a method and an apparatus for monitoring a vehicle status by detecting an impact on a vehicle and comparing the impact applied with a predetermined threshold value, an more particularly, to a method and an apparatus for monitoring a vehicle status, when the vehicle takes an impact, for detecting the vehicle status, determining whether the vehicle is in an abnormal status with a high precision, and allowing a quick and efficient maintenance of the vehicle.
2) Description of the Related Art
Conventionally, when a vehicle running on a road takes some sort of impact, it is a general method to detect an impact value using a sensor installed in the vehicle, and to determine whether there is a possibility that the vehicle is in an abnormal status based on the impact value detected. The vehicle is equipped with a variety of sensors including a steering-angle sensor that detects a steering angle of the vehicle, a G-sensor that detects a vibration in a direction of side to side and up and down, and an acceleration sensor that detects a change of an acceleration of the vehicle, and when any one of the sensors detects an impact value over a predetermined threshold value, a message indicating that an abnormal status occurred in the vehicle is displayed on a front panel of the vehicle (see, for example, Japanese Patent Application Laid-Open Publication No. 2001-184578).
In this case, when the impact value detected is much greater than it should be, a measure of switching a mode of the vehicle to a fail-safe mode is also carried out automatically to make assurance doubly sure on a measure for safety, notifies a driver of the vehicle of an abnormal status, and at the same time, notifies a vehicle dealer of the abnormal status to prepare a necessary part in advance, so that a quick failure recovery is carried out for sure (see, for example, Japanese Patent Application Laid-Open Publication No. 2002-323410).
However, when a vehicle takes an impact, even if it is determined whether the vehicle is in an abnormal status by simply comparing a detected value with a threshold value, as described above according to the conventional technology, a result of the determination may not indicate a status of the vehicle correctly. Generally, the threshold value is set to a considerably high value so that it is not determined that the vehicle is in an abnormal status until a strong impact is posed that a driver or a passenger of the vehicle is injured by the impact. Therefore, even if the impact value detected is lower below the threshold value, the status of the vehicle may become abnormal later. For this reason, in practice, when a vehicle takes some sort of impact, a driver of the vehicle has to monitor the status of the vehicle from that time on, and to determine whether the vehicle is in an abnormal status.
In addition, when it is determined that the vehicle is in an abnormal status, the driver has to take the vehicle to a car body shop such as a car dealer, or when the abnormal status is not conspicuous, has to make a test again, resulting in a considerable effort and a considerable time required for determining whether the vehicle is in an abnormal status.